HIV protease inhibitor nelfinavir inhibits growth of human melanoma cells by induction of cell cycle arrest

HIV protease inhibitors (HIV PI) are a class of antiretroviral drugs that are designed to target the viral protease. Unexpectedly, this class of drugs is also reported to have antitumor activity. In this study, we have evaluated the in vitro activity of nelfinavir, a HIV PI, against human melanoma cells. Nelfinavir inhibits the growth of melanoma cell lines at low micromolar concentrations that are clinically attainable. Nelfinavir promotes apoptosis and arrests cell cycle at G(1) phase. Cell cycle arrest is attributed to inhibition of cyclin-dependent kinase 2 (CDK2) and concomitant dephosphorylation of retinoblastoma tumor suppressor. We further show that nelfinavir inhibits CDK2 through proteasome-dependent degradation of Cdc25A phosphatase. Our results suggest that nelfinavir is a promising candidate chemotherapeutic agent for advanced melanoma, for which novel and effective therapies are urgently needed.     

矢车菊-3-O-葡萄糖苷增强肝癌HepG2细胞的抗肿瘤活性及其机制探讨

目的:探讨矢车菊-3-O-葡萄糖苷(cyanidin-3-glucoside, C3G)增强人肝癌HepG2细胞的抗肿瘤活性及其作用机制。方法:采用MTT法研究C3G对HepG2细胞抑制率的影响;利用激光共聚焦观察Hoechst 33342染色后细胞形态;流式细胞分析仪分别测定C3G对HepG2细胞凋亡、周期和线粒体膜电位的影响;Western blot法测定C3G对HepG2细胞凋亡相关蛋白表达量的影响。结果:当C3G浓度在12.5～100.0μmol/L范围内,随C3G浓度增加HepG2细胞的抑制率显著增加,呈浓度依赖性,同时在24、48、72 h对HepG2细胞抑制率的IC₅₀分别为97.16、40.35、39.83μmol/L。C3G能显著增加HepG2细胞凋亡率和细胞核的荧光强度,并将细胞周期阻滞在G₂/M期,同时线粒体膜电位显著降低。C3G可上调Bax、Cytochrome c、Caspase-9和Caspase-3蛋白表达水平,下调Bcl-2蛋白表达水平。结论:C3G可通过激活线粒体介导的凋亡通路和周期阻滞来实现抗肿瘤作用。     

鸦胆子油对人肝癌细胞增殖的抑制作用及机制

目的:探讨鸦胆子油对人肝癌HepG2和Huh7细胞的增殖抑制作用及机制。方法:采用MTT法分析不同浓度鸦胆子油的增殖抑制作用,并用流式细胞仪进行细胞周期和细胞凋亡分析。结果:鸦胆子油能够使HepG2细胞和Huh7细胞的存活率降低,HepG2细胞24h和48h的IC50值分别为59.41μl/L和45.35μl/L,Huh7细胞24h和48h的IC50值为273.43μl/L和103.52μl/L。细胞周期实验中细胞G0/G1期比例升高。细胞凋亡实验中HepG2和Huh7细胞早期凋亡和晚期凋亡的比例均有增加,但晚期凋亡的细胞比例增加更大,分别为(61.47±7.74)%和(69.34±6.42)%。 结论:鸦胆子油能够抑制HepG2细胞和Huh7细胞的增殖,且通过阻滞细胞周期于G0/G1期诱导细胞凋亡。     

Nelfinavir induces radiation sensitization in pituitary adenoma cells

Pituitary adenomas with local invasion and high secretory activity remain a therapeutic challenge. The HIV protease inhibitor nelfinavir is a radiosensitizer in multiple tumor models. We tested nelfinavir as a radiosensitizer in pituitary adenoma cells in vitro and in vivo. We examined the effect of nelfinavir with radiation on in vitro cell viability, clonogenic survival, apoptosis, prolactin secretion, cell cycle distribution, and the PI3K-AKT-mTOR pathway. We evaluated tumor growth delay and confirmed nelfinavir's effect on the PI3K-AKT-mTOR pathway in a hind-flank model. Nelfinavir sensitized pituitary adenoma cells to ionizing radiation as shown by viability assays and clonogenic assay with an enhancement ratio of 1.2 (p < 0.05). There is increased apoptotic cell death, as determined by annexin-V expression and cleaved caspase-3 levels. Nelfinavir does not affect prolactin secretion or cell cycle distribution. In vivo, untreated tumors reached 4-fold volume in 12 days, 17 days with nelfinavir treatment, 27 days with radiation 6 Gy, and 41 days with nelfinavir plus radiation (one-way ANOVA p < 0.001). Decreased phospho-S6 on Western blotting in vitro and immunohistochemistry in vivo demonstrated nelfinavir inhibition of the PI3K-AKT-mTOR pathway. Our data suggests a promising combination therapy with nelfinavir plus radiation in pituitary adenomas, which should be investigated in clinical studies.     

HIV-1Vpr体外诱导肿瘤细胞凋亡与细胞周期阻滞的研究

目的 研究HIV-1 Vpr诱导Hela、Lovo、HepG2细胞凋亡和G2期阻滞效果.方法 构建含有HIV-1 Vpr基因的pcDNA4-Vpr重组载体,体外转染Hela、Lovo、HepG2细胞,同时设pcDNA4-EGFP质粒转染对照组、FUGENE组和空白对照组.转染后24、48、72 h,通过甲臜化合物法检测...     

Resveratrol inhibits oral squamous cell carcinoma through induction of apoptosis and G2/M phase cell cycle arrest

The present study was performed to investigate the effect of resveratrol (trans-3,4′,5-trihydroxystilbene) present as a natural phytoalexin in grapes, peanuts, and red wine on oral squamous cancer cell lines, SCC-VII, SCC-25, and YD-38. MTS assay and flow cytometry, respectively, were used for the analysis of inhibition of cell proliferation and apoptosis. Western blot analysis was performed to examine the effect of resveratrol on the expression of proteins associated with cell cycle regulation. The results revealed a concentration- and time-dependent inhibition of proliferation in all the three tested cell lines on treatment with resveratrol. The IC₅₀ of resveratrol for SCC-VII, SCC-25, and YD-38 cell lines was found to be 0.5, 0.7, and 1.0 μg/ml, respectively, after 48-h treatment. Examination of the cell cycle analysis showed that resveratrol treatment induced cell cycle arrest in the G2/M phase and enhanced the expression of phospho-cdc2 (Tyr 15), cyclin A2, and cyclin B1 in the oral squamous cell carcinoma (OSCC) cells. It also caused a marked increase in the percentage of apoptotic cells as revealed by the fluorescence-activated cell sorting analysis. Thus, resveratrol exhibits inhibitory effect on the proliferation of OSCC oral cancer cells through the induction of apoptosis and G2/M phase cell cycle arrest.     

S-Trityl-L-Cysteine诱导HL-60细胞有丝分裂阻滞和凋亡

目的研究 S-三苯甲基-L-半胱氨酸（S-Trityl-L-Cysteine,STLC）对急性白血病 HL-60细胞有丝分裂阻滞和凋亡的影响,初步探讨药物作用下HL-60细胞有丝分裂阻滞和凋亡间的因果关系。方法将HL 60细胞分成不加药对照组和不同剂量 (1、2.5、5、10、50、100 μmol/L) STLC加药组,药物作用一定时间后,台盼蓝染色观察HL-60细胞活性变化, MTT法检测其对HL 60细胞的抑制效应, 免疫荧光染色观察细胞及其核的特征,流式细胞术分析细胞周期和亚二倍体峰的变化,Annexin-v/PI双染检测药物处理前后正常骨髓细胞凋亡比率。结果MTT和台盼蓝染色实验显示STLC抑制HL-60细胞生长并致其死亡;免疫荧光染色见核破裂及凋亡小体和细胞体积增大等典型有丝分裂灾变细胞凋亡现象;细胞周期和凋亡分析表明 STLC 致HL-60细胞凋亡比率与药物浓度和作用时间呈正相关,致G₂/M期阻滞比率24 h和48 h随药物浓度增加而升高,而72 h无明显变化,进一步研究发现STLC处理早期即可致G₂/M期有丝分裂阻滞和凋亡的同时发生,撤除药物作用后有丝分裂阻滞呈可逆性恢复,STLC作用下正常骨髓细胞凋亡比率无明显变化。结论STLC诱导HL-60细胞阻滞在G₂/M期并致其凋亡,显示较强的抗有丝分裂和抗肿瘤效果,药物处理早期有丝分裂阻滞和凋亡同时发生提示尚有该药物作用新机制的存在。     

NVP-BEZ235对肝癌HepG2细胞增殖、凋亡及侵袭转移的影响

目的探讨PI3K／Akt／mTOR双靶点抑制剂NVP-BEZ235在体外对肝癌HepG2细胞增殖、凋亡及侵袭转移的影响。方法 采用0、0.01、0.1、1.0μmol／L NVP-BEZ235 处理HepG2细胞,四甲基偶氮唑盐（MTT）比色法检测不同浓度NVP-BEZ235处理24、48、72和96h的增殖抑制率,流式细胞仪、Transwell侵袭实验、荧光定量PCR及免疫印迹检测不同浓度NVP-BEZ235处理48h后的细胞周期分布、穿膜细胞数及基质金属蛋白酶（MMP）-2的mRNA和蛋白水平。结果NVP-BEZ235可呈剂量和时间依赖的方式升高增殖抑制率（P＜0.05）;除0.01μmol／L处理24h的晚期凋亡率外,0.01、0.1、1.0μmol／L NVP-BEZ235处理24、48h的早、晚期凋亡率均高于0μmol／L（P＜0.05）;0.01、0.1、1.0μmol／L NVP-BEZ235处理48h的G0／G1期细胞比例高于0μmol／L,穿膜细胞数、MMP-2 mRNA和蛋白水平及S期和G2／M期细胞比例均低于0μmol／L（P＜0.05）,且各浓度间的差异均有统计学意义（P＜0.05）。结论NVP-BEZ235可抑制肝癌HepG2细胞增殖及侵袭转移,促进其凋亡和阻滞细胞在G0／G1期并降低MMP-2表达。     

尼美舒利对不同COX-2表达水平的食管鳞癌细胞的抑制作用

目的：比较选择性环氧合酶-2（COX-2）抑制剂尼美舒利对不同COX-2表达水平的食管鳞癌细胞的抑制作用。方法：选取食管鳞癌细胞株EC 109、KYSE 150和TE-1,采用Western blot方法测定COX-2蛋白表达、MTT法检测细胞增殖抑制,流式细胞术检测细胞周期和细胞凋亡,观察尼美舒利对各组细胞的增殖抑制和促凋亡作用。结果：COX-2蛋白在EC 109细胞中呈高表达,KYSE 150细胞中呈中等度表达,TE-1细胞不表达COX-2蛋白。尼美舒利在50μmol/L-400μmol/L浓度区间可抑制EC 109、KYSE 150细胞的增殖（P〈0.05）,并呈剂量依赖性,在400μmol/L时对TE-1细胞有抑制作用。EC 109细胞尼美舒利的IC50值最低,KYSE150次之,TE-1最高。尼美舒利可使EC 109和KYSE 150的细胞周期阻滞于G0/G1期,并诱导细胞凋亡,但对TE-1细胞无上述作用。结论：尼美舒利对表达COX-2的食管鳞癌细胞有较好的增殖抑制和促凋亡作用。     

Nelfinavir, A lead HIV protease inhibitor, is a broad-spectrum, anticancer agent that induces endoplasmic reticulum stress, autophagy, and apoptosis in vitro and in vivo.

PURPOSE: The development of new cancer drugs is slow and costly. HIV protease inhibitors are Food and Drug Administration approved for HIV patients. Because these drugs cause toxicities that can be associated with inhibition of Akt, an emerging target in cancer, we assessed the potential of HIV protease inhibitors as anticancer agents. EXPERIMENTAL DESIGN: HIV protease inhibitors were screened in vitro using assays that measure cellular proliferation, apoptotic and nonapoptotic cell death, endoplasmic reticulum (ER) stress, autophagy, and activation of Akt. Nelfinavir was tested in non-small cell lung carcinoma (NSCLC) xenografts with biomarker assessment. RESULTS: Three of six HIV protease inhibitors, nelfinavir, ritonavir, and saquinavir, inhibited proliferation of NSCLC cells, as well as every cell line in the NCI60 cell line panel. Nelfinavir was most potent with a mean 50% growth inhibition of 5.2 micromol/L, a concentration achievable in HIV patients. Nelfinavir caused two types of cell death, caspase-dependent apoptosis and caspase-independent death that was characterized by induction of ER stress and autophagy. Autophagy was protective because an inhibitor of autophagy increased nelfinavir-induced death. Akt was variably inhibited by HIV protease inhibitors, but nelfinavir caused the greatest inhibition of endogenous and growth factor-induced Akt activation. Nelfinavir decreased the viability of a panel of drug-resistant breast cancer cell lines and inhibited the growth of NSCLC xenografts that was associated with induction of ER stress, autophagy, and apoptosis. CONCLUSIONS: Nelfinavir is a lead HIV protease inhibitor with pleiotropic effects in cancer cells. Given its wide spectrum of activity, oral availability, and familiarity of administration, nelfinavir is a Food and Drug Administration-approved drug that could be repositioned as a cancer therapeutic.     

吲哚美辛诱导肝癌HepG2细胞凋亡及其对cyclin E蛋白表达的影响

目的　观察吲哚美辛诱导肝癌 Hep G2细胞凋亡 ,及其对 cyclin E蛋白的影响。方法　采用 MTT比色法观察吲哚美辛对肝癌 Hep G2细胞增殖的影响 ;采用流式细胞仪检测吲哚美辛对 Hep G2细胞周期分布的影响 ,同时结合透射电子显微镜观察吲哚美辛诱导肝癌 Hep G2细胞凋亡的作用 ;免疫细胞化学方法观察吲哚美辛对Hep G2细胞周期调控蛋白 cyclin E的影响。结果　吲哚美辛可抑制肝癌 Hep G2细胞的增殖 ,诱导其凋亡 ,改变细胞周期分布 ,使 G0 /G1 期细胞比例增高 ,S期比例降低 ,同时还可使 cyclin E蛋白表达下降。上述作用具有剂量和时间依赖性 (P<0 .0 5 )。结论　吲哚美辛可诱导肝癌 Hep G2细胞凋亡 ,改变细胞周期分布 ,影响细胞周期调控蛋白表达 ,从而抑制细胞增殖。     

Inhibition of cell growth and induction of G1-phase cell cycle arrest in hepatoma cells by steroid extract from Meretrix meretrix

In this study, we report that the steroid extract 5alpha, 8alpha-epidioxycholest-6-ene-3beta-ol (MME) from Meretrix meretrix has the ability to inhibit growth of hepatoma cells and to induce G1-phase cell cycle arrest in two human hepatoma cell lines, HepG2 and Hep3B. HepG2 cells were more sensitive than Hep3B to MME. The extract markedly up-regulated the expression of p53 and p21WAF1/CIP1 in HepG2, suggesting that MME-induced G1 phase cell cycle arrest in HepG2 might be p53-dependent. Therefore, the up-regulation of p27KIP1and p16INK4A in both cell lines indicates that a p53-independent pathway might be involved in the mechanism of MME inducing cell cycle arrest. In conclusion, MME induces G1 phase cell cycle arrest via both p53-dependent and p53-independent pathways.     

In vitro evaluation of flavopiridol, a novel cell cycle inhibitor, in bladder cancer

Purpose: To determine the in vitro effects of flavopiridol on bladder cancer cell lines, immortalized urothelial cell lines, and normal urothelial cells well characterized for defects in p53, pRb, and p16. Methods: Growth inhibition was assessed via an MTT assay and apoptosis via DAPI nuclear staining. Cell cycle analysis was performed via propidium iodide staining and fluorescent activated cell sorting (FACS). Multidrug-resistant cells were generated by continuous exposure to doxorubicin. Results: Growth inhibition was not correlated with inactivation of p53, pRb, or p16. All cells experienced G2/M arrest within 24 h of flavopiridol exposure. Modest apoptosis was observed but required 72 h of continuous drug exposure to become evident. There was no obvious synergistic or antagonistic toxicity when flavopiridol was combined with radiotherapy or cisplatin dosed at the IC₅₀ despite the observation that radiotherapy and flavopiridol led to more profound G2/M arrest than either agent alone. Doxorubicin-resistant cells, demonstrated to overexpress the MDR1 multidrug-resistance protein were equally as sensitive to flavopiridol as the parental cells. Conclusions: Flavopiridol is a novel cell cycle inhibitor that may be a useful agent in bladder cancers with tumor suppressor gene alterations and/or multidrug resistance. Received: 7 July 1998 / Accepted: 28 October 1998     

Antitumour activity of oxaliplatin in neuroblastoma cell lines

Oxaliplatin appears non cross-resistant with cisplatin and has a comparable antitumour effect both in preclinical and clinical studies. We compared the antitumour effect of oxaliplatin with that of cisplatin in human neuroblastoma cell lines SK-N-DZ, LAN-1 and BE(2)M17 following 24 h exposure at concentrations ranging from 0.5 to 5 microM. Oxaliplatin was less potent with IC50 values 1.08-3.4-fold higher than cisplatin. Like cisplatin, oxaliplatin induced a cell cycle block in the G2/M phase although to a lesser extent than that caused by cisplatin. The concomitant increase of DNA fragmentation and decrease of G2/G1 ratio at 72 h indicated that a fraction of blocked cells underwent apoptosis. Morphological analysis confirmed these data, although oxaliplatin appeared to be 2-3 times less potent than cisplatin in inducing apoptosis. Our results indicate that oxaliplatin is active in neuroblastoma in vitro and this finding warrants in vivo preclinical studies.     

Growth arrest induced by C75, A fatty acid synthase inhibitor, was partially modulated by p38 MAPK but not by p53 in human hepatocellular carcinoma

C75, a well-known fatty acid synthase (FAS) inhibitor, has been shown to possess potent anti-cancer activity in vitro and in vivo. In this study, we reveal that C75 is a cell cycle arrest inducer and explore the potential mechanisms for this effect in hepatocellular carcinoma (HCC) cell lines with abundant FAS expression: HepG2 and SMMC7721 cells with wt-p53, and Hep3B cells with null p53. The results showed FAS protein expression and basal activity levels were higher in HepG2 cells than in the other two HCC cell lines. Treatment with C75 inhibited FAS activity within 30 min of administration and induced G(2) phase arrest accompanied by p53 overexpression in HepG2 and SMMC7721 cells. By contrast, C75 triggered G(1) phase arrest in Hep3B cells, and RNA interference targeting p53 did not attenuate C75-induced G(2) arrest in HepG2 cells. Similarly, p53 overexpression via p53 plasmid transfection did not affect C75-induced G(1) phase arrest in Hep3B cells. However, we observed a clear correlation between p38 MAPK activation triggered by C75 and the induction of cell cycle arrest in all three HCC cells. Furthermore, treatment with the p38 MAPK inhibitor SB203580 reduced p38 MAPK activity and cell cycle arrest, and also partially restored cyclin A, cyclin B1, cyclin D1 and p21 protein levels. Collectively, it was p38 MAPK but not p53 involved in C75-mediated tumor cell growth arrest in HCC cells.     

Thermal enhancement of oxaliplatin-induced inhibition of cell proliferation and cell cycle progression in human carcinoma cell lines

Hyperthermia is used to treat intraperitoneal colorectal carcinomatosis. In this setting, the molecular effects of oxaliplatin and hyperthermia, in combination and alone, were deciphered in ovarian and colon cancer cells. The combined antiproliferative effects of hyperthermia and oxaliplatin (Eloxatine?;) on human IGROV-1 ovarian carcinoma, Caco-2 and HT-29 colon carcinoma cell lines were investigated by cell viability test, cell cycle analysis and modulation of expression of cell cycle-related proteins. Oxaliplatin inhibited growth of all cell lines in a dose-dependent manner. The efficacy of the drug was markedly enhanced by concurrent exposure to mild heat shock (1?h, 42°C). In IGROV-1 cells, a low concentration (15?µg/ml) of oxaliplatin in combination with hyperthermia induced a transient G2/M arrest. In both colon carcinoma cell lines, a G1/S arrest with a reduction of the G0/G1 population occurred. In IGROV-1 and Caco-2 cells, growth arrest was accompanied by apoptosis as suggested by the appearance of sub-G1 population. Time-course changes of cell cycle regulatory proteins levels revealed accumulation of cyclins A and B as well as of cdc2 and cdk2 upon exposure of IGROV-1 cells to hyperthermia and oxaliplatin. In this cell line, p53 appeared to be implicated in both G2/M arrest and apoptosis. G1/S arrest of HT-29 cells was linked to up-regulation of cyclin E and p27^Kip1 and accumulation of the hypophosphorylated form of pRB, whereas in Caco-2 cells only the hyperphosphorylated form was detected as well as a down-regulation of the proto-oncogene c-myc. Taken together, the results of these in vitro studies suggest that hyperthermia and oxaliplatin might elicit antiproliferative effects by modulating the expression of cell cycle regulatory proteins through different signalling pathways.     

Doxorubicin-induced apoptosis and chemosensitivity in hepatoma cell lines

PURPOSE: Doxorubicin (DOX) is a commonly used anticancer drug which causes DNA damage and kills cancer cells mainly by apoptosis. However, the process leading to killing of cancer cells and the molecular basis of resistance to DOX are not well understood. To evaluate the role of p53 and the cellular effects of DOX on hepatoma cell lines, we examined three hepatoma cell lines with different p53 status--Huh-7 (mutated p53), HepG2 (wild-type p53) and Hep3B (deleted p53). METHODS: The chemosensitivity of the three hepatoma cell lines was assessed using the MTT assay, and cell cycle distribution was evaluated by flow cytometry. Western blotting and immunostaining were employed to examine the protein alterations in response to DOX treatment, and a DNA fragmentation assay was performed to detect apoptosis. RESULTS: Of the three cell lines, HepG2 was found to be most resistant to DOX, followed by Hep3B, and Huh-7 was most sensitive to DOX treatment. HepG2 showed G1 arrest 24 h after drug administration and upregulation of p53 protein level in a time-dependent manner. In Hep3B cells (deleted p53), G2/M phase arrest was observed soon after drug administration, accompanied by induced apoptosis that was p53-independent. In Huh-7 cells (mutated p53), which were most sensitive to DOX, there was neither G1 nor G2 arrest, and the level of p53 mutated protein was downregulated after DOX treatment. MDM2 and p27 proteins were downregulated in all cell lines independently of p53 status. p21 was upregulated following p53 activation at low doses of DOX in HepG2 cells, but at higher doses, p21 was downregulated in Huh-7 and HepG2 cells. CONCLUSION: DOX confers different chemosensitivity on different hepatoma cell lines with different p53 status. The contrasting relationships between chemosensitivity and p53 status and expression suggest that DOX-induced apoptosis and cell death involve pathways that are independent of p53.     

All-trans-retinoic acid induces cell growth arrest in a human medulloblastoma cell line

Medulloblastomas (MBs) are the most common malignant brain tumors of childhood. Antitumor agents promoting long-term survival with limited toxicities are thus far lacking. Preliminary findings suggest that retinoic acid (RA) derivatives (retinoids) exert antitumor effects by inhibiting cell proliferation and inducing cell differentiation, apoptosis, and growth arrest, and RAs have been specifically shown to induce apoptosis in some MB cells. However, there is no conclusive evidence of retinoids inducing cell growth arrest in MBs. The aim of this study is to investigate whether retinoids play a role in cell-cycle arrest of MB cells. All-trans-retinoic acid (ATRA) was selected for these studies as it is known to have the capacity of inducing cell cycle arrest and apoptosis in other types of cancer cells. Three MB cell lines (DAOY, D283 and D341) were subjected to ATRA treatment. The proportions of cells in the G0/G1 phase of cell cycle and in apoptosis were evaluated. The results showed that cell growth arrest, rather than apoptosis, was the main mechanism by which RA inhibited cell proliferation in the MB cell line DAOY, but not in the others (D283 and D341). Decreased expression of CyclinD1 and C-myc which regulate the transition of cell cycle was observed in DAOY cells following drug treatment, suggesting that these genes might be involved in ATRA retardation of cell cycle progression. Expression of RARβ, a mediator of the action of retinoids, was also induced by RA in DAOY cells, implying that RAR-β might also be involved in the mechanism of RA-induced cell cycle arrest. In conclusion, we have provided evidence for the first time that RA may induce cell cycle arrest in vitro in DAOY MB cells via inhibition of CyclinD1 or C-myc.